S-91273A166 1/4"-28 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh environments and extended service life.
• High mechanical strength and durability with 70,000 psi tensile strength and 35,000 psi shear strength for demanding applications.
• Precise alignment and smooth rotation ensured by the Class 2A thread fit and standard shoulder fit, reducing wear on mating parts.
• Secure, non-slip installation provided by the knurled socket head and 1/8" hex drive, allowing for high torque application.
• Excellent dimensional stability with tight tolerances on the shoulder diameter and length for consistent performance in assemblies.
• Reliable performance in fine-thread applications due to the 1/4"-28 UNF thread, offering better adjustment and vibration resistance.
• Compliance with major environmental regulations including RoHS 3 and REACH, ensuring safety and suitability for global markets.

Professional Applications & Engineering Value

This stainless steel shoulder screw is engineered to address critical challenges in precision machinery, such as maintaining alignment in rotating assemblies and reducing wear in high-stress pivot points. The 18-8 Stainless Steel material provides excellent corrosion resistance, making it suitable for use in humid or chemically aggressive environments like food processing or marine equipment. The UNF fine thread and Class 2A fit ensure secure fastening with minimal risk of loosening under vibration, which is essential in automotive, aerospace, and industrial automation applications. The knurled socket head with a 1/8" hex drive allows for easy, high-torque installation without slippage, enhancing assembly efficiency and reliability in tight spaces.

Specification Summary & Compliance

This shoulder screw features a 1/4"-28 UNF fine thread with a Class 2A thread fit for precise engagement, and shoulder dimensions including a diameter of 1/4" (tolerance: -0.004" to -0.002") and length of 3/8" (tolerance: -0.005" to 0.005") to ensure consistent performance. Manufactured from 18-8 Stainless Steel with a hardness of Rockwell B55, it meets industry standards for strength and durability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for various industrial and commercial applications.